1. Field of the Invention
The present invention relates to a mounting unit for a head mounted apparatus to be worn on a user's head.
2. Description of the Related Art
A head mounted apparatus with an image display portion to be worn on a user's head (in front of user's eyes) allowing the user to enjoy what's being displayed on the image display portion has been proposed. For this type of head mounted display apparatus, a mounting unit which comprises a front frame having a portion that presses to the front of the user's head and a rear frame having a portion that presses to the back of his/her head. The mounting unit is constituted so that the position of the rear frame with respect to the front frame can be adjusted to fit the head size of the user in a back and forth direction.
Further, to allow for such size adjustment, operation knobs which move together with the rear frame, and locking mechanisms which lock the rear frame into an arbitrary position with respect to the front frame, and lock release buttons for releasing the lock of the locking mechanisms are provided on the mounting unit.
In a conventional size adjustable mounting unit, the operation knobs and the lock release buttons are provided on both side surfaces of the front frame, and saw tooth-like projections are provided on the rear frame. In this unit, the adjusted position of the rear frame with respect to the front frame is fixed by engaging the locking mechanisms with any projection.
In Japanese Patent laid-open 2002-44566 (corresponding to US Patent Application Publication No. 2002-0008677), a mounting unit in which saw tooth-like projections are provided on the front frame and the operation knobs and lock release buttons are provided on both side surfaces at the tips of the rear frame, integrally having a portion pressing to the user's head, is proposed.
In the above-mentioned conventional size adjustable mounting unit, the lock mechanisms for maintaining a state where size adjustment is carried out, and the lock release buttons are provided on both side surfaces of the frame. For this reason, whether a user was to wear the unit or remove the unit from his/her head, neither the size adjustment operation nor lock release operation could be performed easily.
In the case where the operation knobs and the lock release buttons are provided on both side surfaces of the frame, such as shown in FIG. 8, the user must support the lower side of the frame 105 with his/her thumb while at the same time grasping the frame 105 from its top side, with his/her middle, ring and little fingers, then with his/her index finger he/she must operate the operation knob 107 and the lock release button 108.
Here, the possible range L1 at which the operation knob 107 can be operated by the index finger is not so large. Since it is necessary to push the lock release button 108 perpendicularly (from the right and left side) to the side of the frame in this case, he/she must have the thumb positioned perpendicularly to the side of the frame, although the operation knob 107 must be operated with the thumb, if it is going to move the operation knob 107.
In this state, the frame is not supported with the thumb, as shown in FIG. 9, the remaining fingers must hold the frame from its top side, this way of holding the frame however is unnatural. Moreover, it is quite easy for the frame, that is, the entire image display apparatus to slip from the users' hands and drop.